Suggest a 400 film

Originally Posted by Gerald C Koch

Tri-X is probably the finest ISO 400 film on the market. Why are you prejudiced against Kodak?

I beg to differ, Tmax, Delta400, Neopan400 are all finer grained than Tri-X in addition HP5+ is comparable grain wise than Tri-X, if developed with the right developer like DD-X it's actually finer IMHO.

Anyway the OP said he doesn't want grain... So my suggestion...

Assuming you are shooting 120, HP5+ will be fine grained enough for you.

If shooing 35mm, either HP5+ or Delta400.

Tmax personally I find very fine but "boring" looking.

Just buy a roll of each, soup them all in DD-X FIRST, see which two you like best, then shoot those two against each other and soup that in Rodinal and you'll probably have the best choice.